A Statistical Ray Analysis of The Scattering of Radio Waves by the Solar Corona

1968 ◽  
Vol 73 ◽  
pp. 972 ◽  
Author(s):  
Joseph V. Hollweg
Keyword(s):  
Solar Corona ◽  
Radio Waves

Radio Measurements of Coronal Magnetic Fields

1994 ◽  
Vol 144 ◽  
pp. 21-28 ◽  
Author(s):  
G. B. Gelfreikh
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Solar Corona ◽  
Active Regions ◽  
High Sensitivity ◽  
Coronal Magnetic Field ◽  
Transverse Magnetic ◽  
Radio Sources ◽  
Radio Waves ◽  
Solar Active Regions

AbstractA review of methods of measuring magnetic fields in the solar corona using spectral-polarization observations at microwaves with high spatial resolution is presented. The methods are based on the theory of thermal bremsstrahlung, thermal cyclotron emission, propagation of radio waves in quasi-transverse magnetic field and Faraday rotation of the plane of polarization. The most explicit program of measurements of magnetic fields in the atmosphere of solar active regions has been carried out using radio observations performed on the large reflector radio telescope of the Russian Academy of Sciences — RATAN-600. This proved possible due to good wavelength coverage, multichannel spectrographs observations and high sensitivity to polarization of the instrument. Besides direct measurements of the strength of the magnetic fields in some cases the peculiar parameters of radio sources, such as very steep spectra and high brightness temperatures provide some information on a very complicated local structure of the coronal magnetic field. Of special interest are the results found from combined RATAN-600 and large antennas of aperture synthesis (VLA and WSRT), the latter giving more detailed information on twodimensional structure of radio sources. The bulk of the data obtained allows us to investigate themagnetospheresof the solar active regions as the space in the solar corona where the structures and physical processes are controlled both by the photospheric/underphotospheric currents and surrounding “quiet” corona.

scholarly journals 58. Results of observations of the scattering of radio waves by the electronic inhomogeneities of the solar corona

1957 ◽  
Vol 4 ◽  
pp. 313-317
Author(s):  
V. V. Vitkevitch
Keyword(s):  
Solar Corona ◽  
Radio Source ◽  
Crab Nebula ◽  
New Method ◽  
Radio Waves ◽  
The Crab Nebula

A new method for the investigation of the solar corona, suggested by us (Vitkevitch, 1951) [1], consists of observing the radio source identified with the Crab nebula (NGC 1952; α = 05h 31m 40s, δ = 22° 10′) when it is covered by the solar corona. This occurs every year on 14–15 June.

Quasi-harmonic faraday-rotation fluctuations of radio waves when sounding the outer solar corona

2000 ◽  
Vol 26 (8) ◽  
pp. 544-552 ◽  
Author(s):  
A. I. Efimov ◽  
L. N. Samoznaev ◽  
V. E. Andreev ◽  
I. V. Chashei ◽  
M. K. Bird
Keyword(s):  
Solar Corona ◽  
Faraday Rotation ◽  
Radio Waves

Scattering of Radio Waves in the Solar Corona

1983 ◽  
Vol 5 (2) ◽  
pp. 208-211 ◽  
Author(s):  
R. D. Robinson
Keyword(s):  
Solar Corona ◽  
Plasma Frequency ◽  
Time Profile ◽  
Index Of Refraction ◽  
Radio Waves

Radiation generated in the solar corona can be drastically altered by refraction and scattering as it escapes. This is especially true for sources having a frequency near the local plasma frequency, where the index of refraction approaches zero. Early investigations of the problem (e.g. Fokker 1965; Steinberg et al. 1971; Riddle 1972, 1974) have shown that the size, shape, location, intensity and time profile for the observed source can all be influenced.

Multi-Frequency Heliograph Observations of Type II Bursts

1975 ◽  
Vol 2 (6) ◽  
pp. 370-373 ◽  
Author(s):  
G.J. Nelson ◽  
R. D. Robinson
Keyword(s):  
Shock Waves ◽  
Solar Corona ◽  
Spectral Type ◽  
Type Ii ◽  
Harmonic Structure ◽  
Radio Waves ◽  
Brightness Temperatures ◽  
Solar Bursts ◽  
Type Ii Bursts

Multi-frequency observations with the Culgoora radioheliograph (Wild 1967); Sheridan et al. 1973) of five solar bursts of spectral type II (Wild et al. 1954) have now been analysed. The spectra of all five bursts show split-banded harmonic structure. Each type II burst passed through only two of the heliograph’s three observing frequencies (160, 80 and 43.25 MHz). Relationships between the positions, sizes and brightness temperatures of the various sources in each burst are presented and summarized; their implications for the propagation of shock waves and radio waves in the solar corona are briefly discussed.

Multibaseline Observations of the Occultation of Crab Nebula by the Solar Corona at Decameter Wavelengths

2000 ◽  
Vol 179 ◽  
pp. 421-422
Author(s):  
K. R. Subramanian
Keyword(s):  
Refractive Index ◽  
Solar Corona ◽  
Radio Source ◽  
Crab Nebula ◽  
Angular Size ◽  
Radio Sources ◽  
Radio Waves ◽  
Apparent Increase ◽  
Pass Through ◽  
Point To Point

Extended abstractInformation about the outer solar corona can be obtained by observing the occultation of radio sources by the solar corona. As the radio waves pass through the corona they get scattered due to the fact that the electron density and consequently the refractive index varies from point to point. The effect of scattering is manifested by an apparent increase in the angular size of the radio source which can be measured by suitable interferometers. We present here multibaseline observations on the occultation of Crab Nebula at 34.5 MHz with baselines extending upto 4.9 km during June 1986 and 1987.

A channel model for the propagation of X-band radio waves through the solar corona

2017 ◽  
Author(s):  
A.J. Stocker ◽  
D.R. Siddle ◽  
E.M. Warrington ◽  
G. Mariotti ◽  
D. Silvestri ◽  
...  
Keyword(s):  
Solar Corona ◽  
Channel Model ◽  
Radio Waves ◽  
X Band
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